Are invasive species stressful? The glucocorticoid profile of native lizards exposed to invasive fire ants depends on the context

Sean P. Graham, Nicole A. Freidenfelds, Christopher J. Thawley, Travis R. Robbins, Tracy Langkilde

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Invasive species represent a substantial threat to native species worldwide. Research on the impacts of invasive species on wild living vertebrates has focused primarily on population-level effects. The sublethal, individual-level effects of invaders may be equally important but are poorly understood. We investigated the effects of invasive fire ants (Solenopsis invicta) on the physiological stress response of a native lizard (Sceloporus undulatus) within two experimental contexts: directly exposing lizards to a fire ant attack and housing lizards with fire ants in seminatural field enclosures. Lizards directly exposed to brief attack by fire ants had elevated concentrations of the stress hormone corticosterone (CORT), suggesting that these encounters can be physiologically stressful. However, lizards exposed for longer periods to fire ants in field enclosures had lower concentrations of CORT. This may indicate that the combined effects of confinement and fire ant exposure have pushed lizards into allostatic overload. However, lizards from fire ant enclosures appeared to have intact negative feedback controls of the stress response, evidenced by functioning adrenocorticotropic hormone responsiveness and lack of suppression of innate immunity (plasma bactericidal capacity). We review previous studies examining the stress response of wild vertebrates to various anthropogenic stressors and discuss how these—in combination with our results— underscore the importance of considering context (the length, frequency, magnitude, and types of threat) when assessing these impacts.

Original languageEnglish (US)
Pages (from-to)328-337
Number of pages10
JournalPhysiological and Biochemical Zoology
Volume90
Issue number3
DOIs
StatePublished - 2017

All Science Journal Classification (ASJC) codes

  • Physiology
  • Biochemistry
  • Animal Science and Zoology

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